2017MNRAS.471.4579G

We present a high-precision timing analysis of PSR J1933-6211, a millisecond pulsar with a 3.5 ms spin period and a white dwarf (WD) companion, using data from the Parkes radio telescope. Since we have accurately measured the polarization properties of this pulsar, we have applied the matrix template matching approach in which the times of arrival are measured using full polarimetric information. We achieved a weighted root-mean-square timing residuals of the timing residuals of 1.23 µs, 15.5 per cent improvement compared to the total intensity timing analysis. After studying the scintillation properties of this pulsar, we put constraints on the inclination angle of the system. Based on these measurements and on χ² mapping we put a 2σ upper limit on the companion mass (0.44 M_☉). Since this mass limit cannot reveal the nature of the companion, we further investigate the possibility of the companion to be a He WD. Applying the orbital period-mass relation for such WDs, we conclude that the mass of a He WD companion would be about 0.26±0.01 M_☉, which combined with the measured mass function and orbital inclination limits, would lead to a light pulsar mass <= 1.0 M_☉. This result seems unlikely based on current neutron star formation models and we therefore conclude that PSR J1933-6211 most likely has a CO WD companion, which allows for a solution with a more massive pulsar.